// 具体装饰器：添加糖
public class SugarDecorator extends CoffeeDecorator {
    public SugarDecorator(Coffee coffee) { super(coffee); }
    @Override
    public String getDescription() { return super.getDescription() + ", Sugar"; }
    @Override
    public double getCost() { return super.getCost() + 0.2; }
}
